Cam operated machine



April 11, 1944. s. L. Boxl-:LL

CAM OPERATED MACHINE 2 sheets-sheet 1 nventor 6/22 C Bore/Z CttornegSFiled Dec. 50, 1941 April w11, 1944- G. L.` BoxELL 2,346,352

CAM OPERATD MACHINE Filed Dec. 30, 1941 2 SheeiZs-SheerI 2 :inventor @y3 i i @/gzzg. oxf

Bg w wy' GtfornegS Patented Apr. ll, 1944 UNITEDl STATES PATENT OFFICECAM OPERATED MACHINE Glen L. Boxell, Greentown, Ind., assgnor to GeneralMotors Corporation, Detroit, Mich., a corporation of DelawareApplication December so, 1941, serial No. 424,897

6 Claims.

The present invention relates to improvements in assembling machines andmore specifically to machines used in production to assemble a pluralityof parts into a unit.

In production of assemblies in which a number of parts are securedtogether to form a unit it is necessary to provide means to clamp `themembers together. Various means may be used, such as rivets, screws,bolts, etc. In mass production it is necessary to assemble the units asfar as possible automatically. I 1

It is therefore an object ofmy invention to provide a means for applyingsecuring means to a plurality of parts to fasten them together in aunit.

vIt is a further object of my invention to provide an assembly machinefor tightening a plurality of securing means to fasten assembly partstogether.

It is a still further object of my invention to provide an assemblymachine as described above which is automatic in its operation.

With the above and other objects in view, which will become apparent asthe specication proceeds, my invention will be best understood byreference to the following specilication and claims and theillustrations in the accompanying drawings, in which Figure l shows aside elevation of the machine;

Figure 2 is a vertical sectional view of the indexing mechanism;

Figure 3 is a sectional view taken on line 3-3 of Figure 2; and

Figure 4 is a vertical sectional view of one of the clamping means forthe work piece.

Referring now to Figure l, the frame oi the machine shown generally at Icomprises a number of members rigidly bolted together and xed in avertical position on a bench 3 in any well known manner. An air-operateddriving mechanism, of any well known type, such as that used for drivingscrews, is shown generally at 5, and is ixed to a support member lslidably mounted for vertical movement on a vertical guide rod 9 xed toa bracket shown generally at which is, in turn, xed to a vertical framepost shown at i3. An air valve |5 for the air-operated driving mechanismhas a valve stem I1 which is operated by a lever I9 pivoted at 2| to thesupport member 1. When the lower beveled end of the lever I9 contactsthe beveled portion 23 of the bracket Hit admits air to the drivingmeans and causes rotation of the driver bit 25 in a well known manner.The driving mechanism is shown in its depressed position with the'bit 25engaged in a screw of the assembly or work piece shown generally at 2,in

which position the air valve kilis opened and rotation of the bit 25takes place.

The work piece 21 is clamped in position on an L-shaped jig member 29 bymeans of manually operable spring 'engaged and released clamping means,shown generally at 3| and in detail in Figure 4, and another springoperated manually released clamping means shown generally at 33 and indetail in Figure 2. The clamping means 3| is adjustably fixed to theframe post I3 by a clamp member 34 to exert downward pressure on thework piece 21 and hold it in engagement with the horizontal surface ofthe jig. The clamping means 33, shown in detail in Figure 2, is pivotedto the jig member 29 and serves to exert horizontal force on the Workpiece to hold it in engagement with the vertical surface of the jig.Suitable locating means are provided on the jig surfaces, such as shown,which extend into depressions in the work piece.

As best shown in Figure 2, this jig number 29 is fixed to a table 35keyed on the upper journal portion 31 of a cylindrical cam member 39.'Ihe cam member also has a lower journal portion 4| and both of thesejournal portions are shown supported for rotation by anti-frictionbearings located in horizontally extending frame members 43 and 45interconnected by vvertical frame members 4l and 49, each havingvertical V-shaped guideways 5| and 53, respectively, as best shown inFigure 3. A crosshead 55 is shown movably mounted in these guideways andis operably connected to a piston rod 51 and piston 59 which is slidablymounted in an air cylinder 6| fixed to a downwardly extending framemember 63, as shown best in Figures 1 and 2.

The crosshead 55 is provided with a cam operating stud 65, and a clamp61 is connected to both the crosshead and a connecting rod 69 which isslidably mounted for vertical movement in aligned bearings in the framemember 43 and the horizontally extending portions of the bracket Theupper end of the connecting rod 69 is connected to the support member 'lfor the airoperated driving mechanismy 5.

The cylindrical cam member33 is provided with a plurality of straightand curved slots in the periphery thereof. The straight slots 1| areshown extending vertically or parallel to the axis of the cylindricalcam member and the curved slots 'i3 are shown extending angularly withrespect to the axis of the cam member between adjacent vertical slots1|. Each curved slot 'I3 extends from a point near the lower extremityof one of the vertical slots 1| to the top of the acl-i jacent verticalslot and the cam stud 65 in the crosshead 55 is shown extending into thebottom portion of one of the vertical slots 1| below the point where anangular slot 13 intersects this vertical slot as best shown in Figure 1.In each vertical slot there is located a movable frog or switch point 15and frog supporting means 11, the details of which are best shown inFigure 2. The frog 15 is pivoted at 19 to the supporting means 11 whichis fixed to the bottom surface of the slot by machine screws.

The frog is provided with a ramp surface 8| extending angularly outwardand downward from a point in the slot below the peripheral surface ofthe cam member 39 to a'portion-83 of the frog which is flush with theperipheral surface of the cam member 39. The frog is also provided witha tail or stop portion 85 which-` contacts vthe bottom of the slot tomaintain the portion 83 flush with the peripheral surface of the cam.member. The portions of the fregare urged to the above mentionedposition by a compression spring 81, the inner end of which is carriedina counterbore 89 in the bottom of the slot and the outer end pressesoutwardly on the inner surface of the frog 15. The bottom of the slot isundercut at 9| to allow sufcient inward movement of the lower end of thefrog by downward movement of the cam stud in each vertical .slot 1| pastthe ramp surface 8l and ush portion 33 of the frog. The portion 83 ofeach frog is provided with an angular surface cut therein,.shown at 93in Figure 1, which is flush with one wall of an angular slot 13extending into a vertical slot when the frog is urged to its outerposition so that after downward movement of the cam stud in a verticalslot past the frog the angular surface 93 thereof serves as a switchpoint and causesthe cam stud to move upward through an angular slot 13to rotate and index the cam member 39 and therefore the table 35, jig 29and work .piece 21 carried by the cam member.

Any number of vertical or straight slots 1 I may be provided in the cammember, as desired, with an angular or `curved slot 13 connecting thestraight slots, and the straight slots may be spaced angularly so thatthe work piece may be indexed to any position desired for the entranceof the driver bit into ascrew of the work piece when the cam stud ismoved successively upward through an angular slot 13 to an adjacentvertical slot 1i and then downwardly to the bottom of a vertical slot.As the cam stud 65 is carried by the crosshead 55 and the drivingmachine is also connected with the crosshead by the connecting rod 69,upward movement of the crosshead causes the driving machine to be movedupward away from one screw and the work to be indexed for driving ofanother screw by the next down stroke of the crcsshead.

The air cylinder 6| and its piston 59 connected to the crosshead servesto reciprocate the crosshead and therefore cause the work to besuccessively indexed for driving of any number of screws on the workpiece in succession and also serves to control the operating mechanismpreviously described for the air valve I to cause the driving machine tooperate when the screw driving mechanism -is moved to lowest or screwengaging position, as shown in Figure l.

v The air cylinder is provided with air openings 95 and 91 at each endfor the entrance of compressed air and exhaust of air therefrom. Anywell-known type of foot-operated valve and piping, arrangement, notshown, may be used to cause upward or downward movement of the piston inthe cylinder to cause successive indexing of the work and successivedriving of screws in the work piece for an upward and downward stroke ofthe piston.

While I have shown the driving means as engaging and tightening a screwit could be used with a rivet or other type of device and should,therefore, not be limited'to screws.

I claim:

l. In a machine of the type described comprising a composite framestructure which includes rotatable work supporting and clamping means,an indexing cam fixed to the work supporting withan indexing slot,movable tool driving means and reciprocating power means for moving thetool drivingV means toward and away from work supporting means and meanson said reciprocating means in constant engagement with said indexingcam slot for also causing rotation of the indexing cam only when thetool driving means is moved away from the work supporting and clampingmeans. v

2. In a machine of the type described comprising a composite framestructure which includes movable indexing means comprising a rotatablecylindrical cam having a plurality of intersecting slots extendingangularly and parallel to the axis of the cam, a reciprocating studmovable in the slots and movable spring biasing mechanicalswitching'means on said cam to cause the stud to pass successivelythrough adjacent angular and parallel slots to index the cam, worksupporting means on the cam, screw driving means movable toward and awayfrom the work supporting means and reciprocating power operated meansoperatively connected to the cam stud and movable screw driving means tocause indexing of the work supporting means on alternate strokes of thepower operated means.

3. In a machine of the type described including a frame, work supportingmeans rotatably mounted thereon, cam indexing means for the worksupporting means, said cam indexing means being provided with paralleland angularly arranged and interconnected slot portions and a studmovable therein, tool driving means movably mounted on the frame andcontrollable power means operatively connected continuously to the toolsupporting means and said stud of said cam indexing means to cause thetool supporting means to move toward and away from the work supportingmeans and to operate the indexing means only upon movement of the toolsupporting means away from the work supporting means.

4. In a machine of the type described including a frame, rotatable worksupporting means mounted on the frame, 'indexing means for the worksupporting means, power operated tool driving means movably `mounted onthe frame, said power operated tool driving means including movablepower control means Vfor controlling 'the application of power thereto,a cam surface on said frame to cause movement of the control means, andcontrollable power means mounted on said frame and operably connected totheztool driving means and indexing means simultaneously to cause thepower operated `tool driving means to be moved toward the worksupporting means an amo-unt necessary for the power control means toengage the frame cam surface and to causeoperation of the tool drivingmeans, said controllable power means lalso being adaptedto cause thepower operated tool driving means and power control means therefor to bemoved awatr from the work supporting means to stop operation thereof andsimultaneously cause operation of the indexing means.

5. In a machine of the type described including a stationary frame, worksupporting means rotatably mounted on the frame, cam indexing means forsaid work supporting means, said cam indexing means including a camoperatively connected to said Work supporting means and having parallelor locking slot portions and angular or indexing slot portions betweensaid parallel portions and an indexing stud movable in said slotportions, driving means supported for reciprocating movement on saidframe, a tool operated by the driving means, and power operated meanssupported on the frame operatively ccn nected directly to both saidindexing stud and said tool driving means to cause reciprocatingmovement thereof, thereby to cause the driving means and tool to bemoved toward the Work supporting means without causing indexing of saidwork supporting means and to cause reverse movement of the driving meansand tool and simultaneous indexing of said work supporting means.

6. In a machine of the type described including a supporting frame, arotatable Work supporting member carried by the frame, indexing meansconnected to the member, the indexing means comprising an indexing camhaving intersecting straight and curved slots, a reciprocable cam studmovable in the slots, and movable spring biased mechanical switchingmeans supported on the cam, said switching means being operable byone-way movement of the stud in the straight slots to cause subsequentmovement of the stud in the curved slots by reverse movement thereof toindex the cam, an air operated screw driving mechanism reciprocablymounted on the frame, said mechanism being operably connected to the camstud and having an air admission valve operable only by contact with aframe projection upon a predetermined movement of the stud in eachstraight slot, and a second air operated mechanism operably connected tothe cam stud to reciprocate both the stud and interconnected airoperated screw driving mechanism relative to the work supporting member.

GLEN L. BOXELL.

